Orthodontic treatment involves the movement of malpositioned teeth to orthodontically correct positions. In some patients, this may include correcting the alignment of the upper dental arch, or maxillary jaw, and the lower dental arch, or mandibular jaw. For example, certain patients have a condition referred to as a Class II malocclusion, or “overbite,” where the lower dental arch is located an excessive distance in a rearward direction relative to the location of the upper dental arch when the jaws are closed. Other patients may have an opposite condition referred to as a Class III malocclusion, or “underbite,” wherein the lower dental arch is located in a forward direction of its desired location relative to the position of the upper dental arch when the jaws are closed. Class II and Class III malocclusions are commonly corrected by movement of the lower dental arch relative to the upper dental arch. In order to minimize the overall length of time by which a patient must undergo orthodontic treatment, it is typically desirable to achieve this correction at the same time that archwires and brackets are used to move individual teeth to desired positions. For example, oftentimes the movement of the lower dental arch is achieved by applying forces to brackets, buccal tubes, archwires, anchors, bands, caps, or attachments connected to these orthodontic appliances.
A number of orthodontic appliances for treating malocclusions have been developed. One of the most popular of such orthodontic appliances is commonly referred to as a “Herbst” device. A conventional Herbst device is comprised of a telescoping sleeve and rod assembly. Typically, one component of the assembly is pivotally secured to a molar tooth in the upper arch, while the other component is pivotally secured to a bicuspid or anterior tooth in the lower arch (or a cantilever arm in the lower arch). Oftentimes, both the sleeve and rod components are pivotally secured to their respective dental arches using a screw that is inserted through an opening or eyelet in the respective components and coupled to a threaded member on the archwire, bracket, cap or other orthodontic appliance.
Herbst devices operate by forcing the lower arch into a desired occlusion position when the mouth is closed. In other words, the Herbst device prevents a patient from comfortably closing his or her mouth unless the arches are physically repositioned for proper occlusion. If the arches are not properly repositioned, the sleeve of the Herbst device impacts an end portion of the rod so as to create a hard, fixed “stop” that is uncomfortable for the patient. To compensate for this uncomfortable stop the patient repositions their mandibular jaw forward. Eventually, the patient experiences physiological adaptation based upon a learned response such that the jaws begin to naturally close with the proper occlusion. As treatment progresses, spacers may be positioned on the rod to properly reposition the hard, fixed stop once the jaws have begun to adapt, thereby permitting continued treatment and further adaptation of the jaws to the proper occlusion.
While Herbst devices are generally successful for moving the jaws over a significant distance and in a relatively short period of time, it is sometimes necessary to follow treatment using a Herbst device with treatment using a spring-biased bite corrector. For instance, it is not uncommon for the jaws to slightly relapse out of proper occlusion after treatment with a Herbst device. In these cases, the relapse is often corrected using a spring-biased bite corrector. To this end, the Herbst device is typically removed from the teeth and mouth of the patient and a separate spring-biased bite corrector is installed on the teeth.
Spring-biased bite correctors may be arranged to generate a push-type force to move the mandibular jaw or teeth forward and typically include a spring or flexible member that applies a biasing force on the mandibular jaw or teeth to achieve movement. The spring is biased when the jaws are closed such that it applies a force generally along the normal growth direction for a human jaw. The connection between a spring-biased bite corrector and the upper and lower arches is typically complex, utilizing multiple separate parts. For instance, the posterior end of the bite corrector is typically coupled to a buccal tube on an upper molar using a bayonet wire or pin which has a first end coupled to the posterior of the bite corrector and a free end that is first threaded through the buccal tube and then bent back on itself thereby coupling the posterior end to the upper arch. The anterior end of the bite corrector typically includes an eyelet, which is positioned on, and moves freely along, the archwire on the lower arch. Alternately, the anterior end of the bite corrector may be positioned on an auxiliary wire associated with the lower arch.
In addition to the above, spring-biased bite correctors may also be used in other orthodontic treatments. For example, if the malocclusion is relatively small, therefore not generally requiring significant muscular and skeletal adaptation, a spring-biased bite corrector may be used in the first instance to correct the malocclusion. Spring-biased bite correctors may also be used in the orthodontic treatment of adult patients where physiological adaptation to the jaw may be more limited.
In any event, there are some drawbacks to the current orthodontic appliances for the treatment of malocclusions as described above. For example, one drawback is that connectors that couple the orthodontic appliances to the teeth or arches may require assembling multiple separate pieces, which may be difficult and time consuming. This may be particularly true if the appliance is coupled to a molar in the posterior of the mouth, therefore having limited accessibility. Moreover, in order to maintain the connections and withstand the forces exerted during orthodontic treatment, the connectors that couple the appliances to the teeth or arches, as well as the tools used to make the connection, are often large and bulky. These components and associated tools may therefore cause patient discomfort through contact with oral tissues. In yet another drawback, current connectors, and especially screw-based connectors, provide very limited movement of the jaws in a lateral direction (i.e., left to right movements). This leads to increased device breakage, as patients attempt to move their jaws in the lateral direction, and is generally uncomfortable for the patient.
Accordingly, there is a need in the orthodontic art for improving the devices and methods for coupling orthodontic appliances to a patient.